After some extensive research, I bought this for my Epiphone Firebird 1963 Reissue and I couldn't be happier!
Despite liking the stock pickup, I replaced it because it didn't have that bite that my Gibson guitars have.
I usually play a Les Paul Traditional Pro with a stock BurstBucker 3 (Alnico 2) and have two SG's both with stock 490Ts (also Alnico 2) that have served as a comparison for sound.
This Mini-humbucker just matched their tone and had approximately the same output as the 490T. I didn't want a standard Firebird pickup since they have tonal qualities that would be closer to a hot-rodded single coil and that wasn't going to be suitable for the music I mostly play.
As said in the description of the product, it gives a tighter sound than standard humbuckers but won't give you any bad frequencies which might have been the case back in the day.
It's simply a great blues/rock/hard rock pickup which doesn't cost a fortune!
So on a budget, I've upgraded my Epiphone Firebird with a killer pickup and can use it as a main guitar now!